<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'OPen Sans', sans-serif;
        }

        body {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            background: #111111;
        }

        .square {
            position: relative;
            width: 500px;
            height: 500px;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .square i {
            position: absolute;
            inset: 0;
            border: 2px solid #fff;
            transition: 0.5s;
        }

        .square i:nth-child(1) {
            border-radius: 38% 62% 63% 37% / 41% 44% 56% 59%;
            animation: animate 6s linear infinite;
        }

        .square i:nth-child(2) {
            border-radius: 41% 44% 56% 59%/38% 62% 63% 37%;
            animation: animate 4s linear infinite;
        }

        .square i:nth-child(3) {
            border-radius: 41% 44% 56% 59%/38% 62% 63% 37%;
            animation: animate2 10s linear infinite;
        }

        .square:hover i:nth-child(1) {
            border: none;
            background: -webkit-linear-gradient(90deg, #6f31eb, #0078ff, #8ab2ed);
        }

        .square:hover i:nth-child(2) {
            border: none;
            background: -webkit-linear-gradient(90deg, #5203f1, #184475, #07d9f5);
        }

        .square:hover i:nth-child(3) {
            border: none;
            background: -webkit-linear-gradient(90deg, #41a8bf, #a044c1, #6f1fbf);
        }

        @keyframes animate {
            0% {
                transform: rotate(0deg);
            }

            100% {
                transform: rotate(360deg);
            }
        }

        @keyframes animate2 {
            0% {
                transform: rotate(360deg);
            }

            100% {
                transform: rotate(0deg);
            }
        }

        .login {
            position: absolute;
            width: 300px;
            height: 100px;
            display: flex;
            justify-content: center;
            align-items: center;
            flex-direction: column;
            gap: 20px;
        }

        .login h2 {
            font-size: 2em;
            color: #fff;
        }

        .login .inputBx {
            position: relative;
            width: 100px;
        }

        .login .inputBx input {
            position: relative;
            width: 100%;
            padding: 12px 20px;
            background: transparent;
            border: 2px solid#fff;
            border-radius: 40px;
            font-size: 1.2em;
            color: #fff;
            box-shadow: none;
            outline: none;
        }

        .login .inputBx input[type="submit"] {
            width: 100%;
            background: none;
            border: 2px solid #fff;
             cursor: pointer;
        }

        .login .inputBx input[type="submit"]:hover {
            background: linear-gradient(45deg, #ff357a#fff172);
        }

        .login .inputBx input::placeholder {
            color: rgba(255, 255, 255, 0.75);
        }

        .login .links {
            position: relative;
            width: 100%;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 20px;
        }

        .login .links a {
            color: #fff;
            text-decoration: none;
        }

        .login a:hover {
            color: #0078ff;
        }
    </style>
</head>

<body>
    <div class="square">
        <i style="--clr:#00ff0a;"></i>
        <i style="--clr:#ff0057;"></i>
        <i style="--clr:#fffd44;"></i>
        <div class="login">
            <h2>登录</h2>
            <div class="inputBx">
                <input type="text" placeholder="用户名">
            </div>
            <div class="inputBx">
                <input type="password" placeholder="密码">
            </div>
            <div class="inputBx">
                <input type="submit" value="登录">
            </div>
            <div class="links">
                <a href="#">忘记密码</a>
                <a href="#">注册</a>
            </div>
        </div>
    </div>
</body>

</html>